Guiding catheters are well known devices used to locate and cannulate vessels for a variety of medical procedures. They are of particular use in cardiac access procedures such as those involved in the implantation of cardiac pacing leads. Cardiac pacing leads are flexible, and historically, stylets have been inserted into the lumen of hollow leads to stiffen and allow the lead to be bent to aid in lead placement. Stylets are still in common use but are inadequate to provide precise control to reach and place a lead at the small target His bundle. Typically, when right side approach is desired it involves accessing the heart via the left subclavian vein, the cephalic vein and more rarely the internal or external jugular vein, or femoral vein. For catheter lead placement, a guide wire is advanced into the heat from the access site. The guiding catheter is then advanced through the vasculature and into the heart over the guidewire; once in position the guidewire is removed. A pacing lead is then advanced through the guiding catheter to be deployed at various regions in the heart.
Typically, pacing leads are deployed to various locations in the heart depending on the nature of the heart condition necessitating the pacing procedure. Conventional ventricular pacing typically involves implanting a lead at the apex of the right ventricle. This placement is still often utilized today even in the face of published evidence of the deleterious effects of bypassing the His/Purkinje system, otherwise known as the cardiac conduction system.
Pacemaker lead electrodes have been placed in or on the heart in a position that bypasses the His/Purkinje system since the inception of pacing in 1957. Directly stimulating the myocardium is and has been the standard of care even though His bundle pacing has been known and tried occasionally. It is believed that His bundle pacing is not widely practiced because it presents a small target and is very hard to reach successfully. This increases “fluro time” which is a detriment to both patient and physician. Another factor is that there is no wide recognition of the value of His pacing. At present there is a paucity of catheters that can facilitate His bundle pacing. When, for various reasons, the pacemaker must be implanted on the patient's right side and right subclavian vein used to reach the heart the target is still the myocardium and not the His bundle. It should be noted for completeness that the His bundle is accessed on the atrial aspect of the annulus of the tricuspid valve, just above the attachment of the septal valve leaflet.
The present disclosure describes embodiments of a catheter and method for its use in delivering a pacing lead to the His bundle at the septal wall. The cardiac conduction system is comprised in part of His bundle which resides between the atrioventricular (AV) node, and the bifurcation of left bundle branch (LBB) and right bundle branch (RBB). This anatomic location is regarded as a difficult target to reach. Embodiments of the present invention have overcome this difficulty.